I rather like using the term 'speculative fiction' as a catch-all for all stories where the-way-things-are has been knowingly changed or built upon. I used to call them What-If stories but 'speculative fiction' works as well.

That said I agree that it's good to know what sort of speculation is taking place. I enjoy hybrid genres but I also like to know if the book I'm considering reading is science fiction, where the change is due to SCIENCE (however fictional); fantasy ,where the change is due to MAGIC; alternative history, where the change is often attributed to chance; or some hybrid genre.

I would argue that the psi powers used by SF writers from the 30's to the 50's, including such names as Asimov, Doc Smith, Marion Zimmer Bradley, Andre Norton, and McCaffery were the functional equivalent of witches. A number of classic SF books used psi powers.

I agree. In my own cataloging many books of that nature are simply tagged as speculative fiction as I can't quite bring myself to consider psi powers when presented as some sort of innate power as even fictional science but I know that they weren't intended to be fantasy.

I agree. In my own cataloging many books of that nature are simply tagged as speculative fiction as I can't quite bring myself to consider psi powers when presented as some sort of innate power as even fictional science but I know that they weren't intended to be fantasy.

That annoys me, too, when they try to make it sound "scientific" by calling it PSI. Now, if they had a plausible reason for the existence of this "power," based in physical reality, then it can be called science fiction. If there is no plausible explanation, then it's magic and fantasy. It's okay to sidestep the problem by using the term "speculative fiction." What I don't like is people assuming that science can be lumped in with fantasy.

That annoys me, too, when they try to make it sound "scientific" by calling it PSI. Now, if they had a plausible reason for the existence of this "power," based in physical reality, then it can be called science fiction. If there is no plausible explanation, then it's magic and fantasy.

An awful lot of SF would fall into the realms of "magic and fantasy", if we were to use that definition. Any book featuring faster-than-light travel, for example. I'm not so picky, myself. I'm happy to accept as SF any technology which is consistent with the "world" of the book, rather than insisting on an explanation with is plausible by the standards of today's science.

An awful lot of SF would fall into the realms of "magic and fantasy", if we were to use that definition. Any book featuring faster-than-light travel, for example. I'm not so picky, myself. I'm happy to accept as SF any technology which is consistent with the "world" of the book, rather than insisting on an explanation with is plausible by the standards of today's science.

What about near instant travel as in Dune? Is that fantasy because the spacing guild navigators mutated and use their mind alone or science fiction because folding space at least doesn't violate FTL travel? If computers were allowed, and they used some device to fold space, does it become pure science fiction?

What about near instant travel as in Dune? Is that fantasy because the spacing guild navigators mutated and use their mind alone or science fiction because folding space at least doesn't violate FTL travel? If computers were allowed, and they used some device to fold space, does it become pure science fiction?

When the current level of understanding of the physical world leaves us with around 85% of the universe's mass described as "dark matter" and around 25% of its energy density described as "dark energy", pretty much anything goes for me in science fiction .

An awful lot of SF would fall into the realms of "magic and fantasy", if we were to use that definition. Any book featuring faster-than-light travel, for example. I'm not so picky, myself. I'm happy to accept as SF any technology which is consistent with the "world" of the book, rather than insisting on an explanation with is plausible by the standards of today's science.

I expect you're right. A lot of those stories were published in Fantastic magazine, weren't they? I'm not a scholar on this; when was the term "science fiction" made popular?

I would replace "plausible by the standards" with "plausible by the implications" of today's science.

I'm not so picky, myself. I'm happy to accept as SF any technology which is consistent with the "world" of the book, rather than insisting on an explanation with is plausible by the standards of today's science.

Sounds like my preference for fantasy. If you are going to use magic, create a set of rules and follow them. Deus ex machina generally means the author painted themselves into a corner and were too lazy to think of a good way out.